Accumulators are known from the state of the art with several accumulators that are switched together as packs or modules and at which the accumulator cells that are arranged in an assigned accumulator housing are electrically connected with each other by so-called cell connectors. The individual accumulator cells are hereby usually welded with the cell connectors, for example by electrical spot welding. During the electrical spot a welding a default heat amount is imported by a corresponding current flow into the material of the accumulator cells and cell connectors that has to be connected in order to melt it at least for a short period of time.
The disadvantage of the state of the art is that the achievable welding quality at the electrical spot welding depends on a selection of applicable welding parameters, for example the duration and current height of the current flow. The selection of the applicable welding parameters depends furthermore on a corresponding construction of the accumulator cells and cell connectors, for example accumulator cell material and—wall material, cell connector material and—thickness. But a selection of different welding parameters might be already required at slight changes of the construction of the accumulator cells and cell connectors in order to maintain a sufficient welding quality.
Furthermore, different welding parameters might be required if different alternative accumulator cells are allowed for a default accumulator type, for example NiCd, NiMh, and Li-Ion. A Li-Ion-cell is moreover problematic in that they are usually very heat-sensitive so that a damage of the cells might occur under circumstances at a too high current flow or a too high energy at the electrical spot welding, which could be helpful for creating a corresponding welding connection. Therefore, the selection of applicable welding parameters is a constant error source at the electrical spot welding of accumulator cells with cell connectors.